Do you hold shares in Smooth On, Daryl? You sure do like EA-40! I understand it is a great product, one that is specifically formulated for bow making, so for that application you can't go far wrong.
greybeard wrote:I believe that if ‘thicker’ epoxies can not be levelled in the bow laminating process one may face a situation where air bubbles are trapped between the laminations. Thicker glue lines could also result if insufficient clamp pressure is applied.
I use what would probably be described as a 'thick', gel-like epoxy (often cured at ambient temperature for 24+ hrs, or the hot box for 4-6 hrs in winter) and have not had delamination failures with it - laminate bows are my 'go-to' design for a confident finished build. I clamp with a mixture of G-Clamps, Spring Clamps, F-Clamps and Quik-Grips, depending on what I have to hand and what is required. I've never had trouble spreading glue but perhaps that just takes a bit of practice for some people.
Using Titebond III, I have had a couple of delamination failures, one of which was from a young woman drawing a 62" child's laminate bow past her ear - remarkably, the Red Oak backing didn't fail. I wouldn't advise against Titebond though, it's worthwhile for a beginner (who might be making a lot of mistakes) and is perfect for gluing straight-grained backings to boards.
greybeard wrote:“Bote-Cote epoxy resin;
We have made this epoxy resin system a bit more flexible so that it is much less likely to crack on a flexing piece of wood and we have thickened the epoxy resin a little bit so it is a lot easier to get a decent film thickness, especially when applying it to sloping or vertical surfaces.”
Those would be very useful properties in boat building applications. Boards, or fiberglass sheets, or whatever materials you are gluing together, aren't always well-dressed and/or flat and it's important that the gap-filling properties of an epoxy are utilised to their optimum. Sometimes the epoxy might not even be used as a glue but instead as a gap filler, or a bridge across a crack, in which case a good film thickness would allow for one coat applied as opposed to several.
greybeard wrote:The suitability of Bote-cote and Norglass for use in bow making is an unknown quantity
With the greatest respect, that is not an entirely true statement. Perry/Jacko has used Bote-cote and (in his words) has never had a delamination failure. I met another individual in Canberra last year who uses a marine epoxy for laminating bamboo-backings and is very satisfied with the results. I am open about using an industrial epoxy for laminate bows and have never had a delamination failure with that product. EA-40 has much broader usage, and therefore has more of a track-record in making bows.
There's very little to stop West Systems copying the chemical make-up of EA-40 and putting their own name to it, selling it cheaply to the Australian market - the product would be an "unknown quantity" but would be the equal of EA-40. Someone would have to test that though and, unless someone did, no-one would ever use it until it had been "proven". Which is a bit of a chicken/egg situation.
As far as the glue debate goes, it's horse for courses, as far as I'm concerned.
- If you are happy to order online/over the phone and are making multiple bows (potentially with glass belly/back), then Smooth On EA-40 is your best bet. There are ways to obtain EA-40 over the counter, but it is taboo to raise this on this forum.
- If you're making multiple board bows and only need to glue handles & nocks, or perhaps timber backing strips, there's no reason not to use Titebond III (unless you need to speed the curing process, in which case an epoxy & a hot box would be quicker). This product is also easy to source in person at Masters or Carbatec.
- If you want to buy your glue in person (this is a personal preference) and/or might be using it in applications other than bowmaking, then Techniglue or a marine/industrial epoxy might be more suitable. On the other hand, EA-40 might be good in certain non-bow applications, but perhaps not as broadly as Techniglue or a marine/industrial epoxy.
- If you're only making a limited number of bows, or perhaps only one, a 1/2 pint pack of EA-40 might be unnecessary, so smaller packs of an alternative epoxy might be better suited to the individual.
- If you only want to buy Australian-made products, EA-40 & Gordon's Glass aren't an option, so you would need to look at alternatives.
There are many bowyers who make multiple bows of varying materials (composites, timber, bamboo, other) who are happy to order glues specific to that task online or over the phone, which is why for the majority, EA-40 will be a great product. There are other bowyers or people-who-sometimes-make-bows that don't quite fit that description, so other products might be better suited for them. It doesn't devalue EA-40 in any way, or make those who use EA-40 superior, it's just different. Thinking outside the square and accepting that other people complete a comparable end result as your own, only using different methods & materials, is a good way to not stress out about these things!
As my old mentor used to say,
"There are many ways to make a chocolate cake, and they're all still chocolate cakes". That guy really loved his chocolate cake.
